Powerbox released a coreless technology platform to power medical and industrial equipment operating in very high magnetic field environments such as magnetic resonance imaging or particle accelerators.

Using high-frequency switching topologies and digital control with firmware to optimize efficiency and voltage regulation, the company says its Powerbox GB350 buck-converter module is able to operate safely when exposed to high radiation magnetic fields of 2 to 4 Tesla.

Powerbox’s GB350 buck-converter module.GB350 delivers an output power of 350W. When higher power levels are required, the company says it can be paralleled using an interleaving mode thus reducing EMI.

Medical and industrial applications such as magnetic resonance imaging (MRI) and particle accelerators (PA) generate high magnetic fields to induce the RF energy required to activate the hydrogen nuclei in the case of imaging, or to accelerate particles in research and industrial equipment.

The company says that modern MRI systems usually generate 1.5 to 4 Tesla, making conventional power supplies using ferrite material "useless due to inductance saturation as a result of the MRI magnet disturbing the energy transfer."

To prevent parasitic saturation, power supplies are traditionally positioned outside the shielded operation room. Installing the power supplies remotely requires long cables with subsequent power losses, and it is also a big challenge to power the latest generation of measuring equipment that require stable and tightly regulated voltages under fast transient load conditions, the company says.

To reduce energy consumption and to guarantee the level of quality required by integrated equipment, systems manufacturers are now integrating local power supplies near to the load, the company says. However, placing equipment directly in the radiated magnetic field requires an innovative power solution known as "coreless power units" and a switching power stage.

Powerbox says its GB350 coreless power unit is controlled by a digital processor that manages the complete power unit from switching parameters to output voltage characterization. To guarantee flexibility and the possibility to re-profile the power unit characteristics when equipment manufacturers upgrade new hardware or implement a software revision, the GB350 micro-controller can be programmed with optimized configuration files downloaded through the digital interface.

The standard GB350 platform delivers a nominal current of 50A and preset output voltages of 6.8, 3.3 or 1.6V. As part of the Powerbox Custom Power Solution toolbox, other output voltages are available on request.

The GB350 has a switching frequency of 600kHz. Equipment installed within the magnetic field often require higher power levels than 350W and also very low EMI. With a switching frequency of 600kHz and its 4 phase interleave mode, the GB350 has a resultant output frequency of 2.4MHz. This allows easier filtering and extremely fast regulation response times. The unit also includes EMI shielding to lower radiated emission.